From: Peter Zijlstra <peterz@infradead.org>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Leo Yan <leo.yan@linaro.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Namhyung Kim <namhyung@kernel.org>,
Andi Kleen <ak@linux.intel.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 2/2] perf auxtrace: Optimize barriers with load-acquire and store-release
Date: Tue, 1 Jun 2021 11:17:46 +0200 [thread overview]
Message-ID: <YLX7OhK37QmfeOwu@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <71b0e395-0e20-fdd1-b105-0ca1706c8ed1@intel.com>
On Tue, Jun 01, 2021 at 12:07:31PM +0300, Adrian Hunter wrote:
> __sync_xxx_compare_and_swap is out-of-date now. This page:
>
> https://gcc.gnu.org/onlinedocs/gcc/_005f_005fsync-Builtins.html#g_t_005f_005fsync-Builtins
>
> recommends '__atomic' builtins instead.
perf doesn't seem to use that.
> Since atomics are needed only for the "compat" case (i.e. 32-bit perf with 64-bit kernel)
> you could try to find an elegant way to check for a 64-bit kernel, and avoid the atomics
> for a 32-bit perf with 32-bit kernel.
Most 32bit archs cannot do 64bit atomics. I suppose the only reason this
doesn't explode is because the aux stuff isn't supported on many
architectures?
next prev parent reply other threads:[~2021-06-01 9:18 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-19 14:03 [PATCH v1 1/2] perf auxtrace: Change to use SMP memory barriers Leo Yan
2021-05-19 14:03 ` [PATCH v1 2/2] perf auxtrace: Optimize barriers with load-acquire and store-release Leo Yan
2021-05-31 15:10 ` Leo Yan
2021-05-31 15:55 ` Peter Zijlstra
2021-05-31 19:03 ` Adrian Hunter
2021-06-01 6:33 ` Leo Yan
2021-06-01 6:58 ` Peter Zijlstra
2021-06-01 9:07 ` Adrian Hunter
2021-06-01 9:17 ` Peter Zijlstra [this message]
2021-06-01 9:45 ` Adrian Hunter
2021-06-01 9:48 ` Peter Zijlstra
2021-06-01 14:56 ` Leo Yan
2021-06-01 6:48 ` Peter Zijlstra
2021-05-27 7:54 ` [PATCH v1 1/2] perf auxtrace: Change to use SMP memory barriers Adrian Hunter
2021-05-27 8:11 ` Peter Zijlstra
2021-05-27 8:25 ` Adrian Hunter
2021-05-27 9:24 ` Adrian Hunter
2021-05-27 9:57 ` Peter Zijlstra
2021-05-31 14:53 ` Leo Yan
2021-05-31 15:48 ` Peter Zijlstra
2021-06-01 3:21 ` Leo Yan
2021-05-27 9:45 ` Peter Zijlstra
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